The Justice Department won’t prosecute former a Ferguson, Missouri, police officer in the shooting death of an unarmed black 18-year-old, but in a scathing report released Wednesday faulted the city and its law enforcement for racial bias.

WASHINGTON — The Justice Department won’t prosecute former a Ferguson, Missouri, police officer in the shooting death of an unarmed black 18-year-old, but in a scathing report released Wednesday faulted the city and its law enforcement for racial bias.

Federal officials concluded there was no evidence to disprove former officer Darren Wilson’s testimony that he feared for his safety, nor was there reliable evidence that Michael Brown had his hands up when he was shot.

The decision in the August 9 shooting had been expected, in part because of the high legal standard needed for a federal civil rights prosecution. Wilson, who has said Brown struck him in the face and reached for his gun during a tussle, also had been cleared by a Missouri grand jury in November and later resigned from the department.

The report said blacks in Ferguson are disproportionately subject to excessive police force, baseless traffic stops and citations for infractions as petty as walking down the middle of the street.

Attention now turns to Ferguson as the city confronts how to fix racial biases that the federal government says are deeply rooted in the police department, court and jail.

Similar federal investigations of troubled police departments have led to the appointment of independent monitors and mandated overhauls in the most fundamental of police practices. The Justice Department maintains the right to sue a police department if officials balk at making changes, though many investigations resolve the issue with both sides negotiating a blueprint for change known as a consent decree.

“It’s quite evident that change is coming down the pike. This is encouraging,” said John Gaskin III, a St. Louis community activist. “It’s so unfortunate that Michael Brown had to be killed. But in spite of that, I feel justice is coming.”

Others said the federal government’s findings confirmed what they had long known and should lead to change in the police department leadership.

Brown’s killing set off weeks of protests and initiated a national dialogue about police use of force and their relations with minority communities. A separate report being issued soon is expected to clear the officer, Darren Wilson, of federal civil rights charges. A state grand jury already declined to indict Wilson, who has since resigned.

The findings of the investigation, which began weeks after Brown’s killing last August, were released as Attorney General Eric Holder prepares to leave his job following a six-year tenure that focused largely on civil rights. The report is based on interviews with police leaders and residents, a review of more than 35,000 pages of police records and analysis of data on stops, searches and arrests.